Gyroscopic directional instrument



Julie 23, 1931. 5. 6. BROWN 1,811,300

I GYROSCOPIC DIREC'PIONAL INSTRUMENT I Filed Dec. 22, 1926 a preferably includingj Beferringto Patented June 23, 1931 SIDNEY GEORGE BROWN,- or NORTH Lemon, Lennon, mourn GYROSCOIEIC DIRECTIONAL IN STBUmT Application filed December 22, 1926, Serial No. 156,487,111! in Great Britain l'ebruary 8, 1926.

tion on either side'of the north point, while similarly in the static type of gyroscopic directional instrument, i. e., the type WlllCh has no north-seeking property but maintains any initial azimuthal direction to which it ma beset, uncorrected errors likewise exist. either type of instrument, therefore, the north-seeking or static, provides on the ship or other vehicle on which the instrument is mounted an invariable datum line fixed in relation to the earths surface and conse-' uently in certain cases such as gunnery or t e like where a cially high degree of accuracy in azimuth is required, such instruments as at present-constructed are inadequate and without means of correction except by checking against the observed bearings of the sun, stars or the like.

tion is to overcome this dific ty.

With such an object T The invention consists in the combination of a north-seeking gyro-compass and a static gyroscopic 'azimuthdndieatihg instrument with means operated in accordance with the deflection in azimuth of these instruments respectively for indicating the difierence of such deflections, such means an appropriate ele-. ment to which such fierence is imparted.

It will be seen that the present invention isbased on the fundamental principle that by comparison of north see and static gyroscopic azimuth-indicating mstruments,.

the actual error of one or both at a given moment may be ascertained and hence an inflriable idling-line deduced or secured.

nort 'ng' gyroseopic compasses the -'error alternates in direction about i mean position while in the static gyroscopic instrument, it is cumulative in a given direction.

accompanying diagrammatic drawings gyroscopic direc- The primary object of the present invengear with both of these spindles.

Fi 1 shows a general arrangement in whic the diiference in the movements in azimuth of a gro-compass and a'static gyro are recorded on a chart 7 Figure 2 is a view of a normal record obtained and Figure 3 is a view of the record in which the movements of the static gyro have been corrected.

In carrying the invention into effect according to the preferred form, as shown in *1- a gyro-compass, A, operates a motor, a in accordance with its deflection in azimuth by way of any suitable form of repeatermechanism, not shownin the drawings such as described for example in U. S. Patent No. 1,419,010, June 6, 1922, the motor a, in turn dri a screwed spindle, b. Similarly a static gyro, B, operates a second motor, 6, by a suitable repeater system likewise not shown in the drawings, this.motor rotating the screwed spindle, a. 'A gear wheel, (1, carried by a frame, '0, slidable along the spindles, b and a, is arranged to The two instruments, A and B, are

' mounted on the ship or other vehicle carrying them their lubber lines oriented similarly or at a given angle. f

The whole arra t is so design regards directions of rotation that if: the

gyro-wheels ofthe instruments, A and B,

are de artmg' from a 'ven datum in the same direction at the sine rate the tendency of the one spindle b, to move the wheel 35 a, in one direction is precisely counterbalanced by the tenden of the spindle, c,

to move it in the other 'on. In other words the mechanism exercises a di fierential action onthe wheel, 11, so as to impart thereto the difl'erenee in the azimuthal mean point while that of the static gyro is continuous in a given direction, the record will normally consist, as shown in Figure 2, of an undulatory line, 1:, the general direction of which is inclined to a datum line, .76, parallel to the direction of motion of the paper on which the record is made.

' --Having obtained such an undulatory line it is easy to insert with a ruler, for example, a straight line, Z, in a mean position which then gives the rate of movement in azimuth of the static gyro, while the undulations on each side thereof show the departure of the gyro-compass at any moment from the true north.

Having by such'means obtained the rate of wander of the static instrument, a correction may be introduced by any suitable means. 20

and carried by the vertical ring, a, of the instrument. In juxtaposition to the magnet one on each side thereof a pair of coils o, 0,

are mounted on the vertical ring of the gyro-mounting, these two coils being connected as shown to a high resistance wire,

" r, along which moves a contact, 1", carried by any suitable part of the frame, 6, the

whole arrangement thus forming a kind ofpotentiometer by means of which a slight 'bias is imparted to the static gyro so thatits wander iscounter-acted.

A typical form of record so obtained is shown in Figure 3, ill-Which the undulations, 8, are disposed about a mean-line, t, parallel to the direction of motion of the chart.

.By virtue of the present invention, the efiect of the motion of the ship or 'other vehicle on which the instruments are mounted is elimin'oated' so that each may afiord, as it were, a datum from which the movements of the other may be observed, controlled or' checked.

So long as a north-seeking and static gyroscope are combined as indicated above,

the use of mechanism for indicating the dif-,

ferenoe of their azimuthal movements, though preferable, is not esesential, all the requisite data being present for determining an invariable datum line of known position from the readings of the two ments and subsequent correlation thereof by graphing or calculation.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is 1. The combination of a north-seeking gyro-compass, an independently acting static gyroscopic azimuth-indicating instrument, and means operated by these instruments for indicating the algebraic sum of their azimuthal deflection.

2. The combination of a north-seeking gyro-compass, an, independently acting static gyroscopic azimuth-indicating instrument and mechanism associated with each of said gyroscopicinstruments, responsive to their respective azimuthal deflections and including a common element whose movement is determined by said deflections and is proportional to their algebraic sum.

3. The combination of anorth-seeln'ng gyro-compass, an independently acting static gyroscopic azimuth-indicating instrument, two elements respectively operatively associated with said gyroscopic instruments and responsive. to their azimuthal deflections, a third element, and means operatively associated with both first mentioned elements and with said third element and adapted to impart to said third element a movement proportional to the-algebraic sum of said deflections.

4:. The combination of a north-seeking gyro-compass, an independently acting static gyroscopic azimuth-indicating instrument, screwed spindles operatively associated with said gyroscopic instruments respectively, each spindle being rotationally responsive to azimuthal deflections of its controlling o, a frame and a gear wheel rotatably mounted in said frame and engaging both of said screwed spindles, said spindles and said gear wheel being so relatively disposed that movement of said gear wheel and said-frame is roportional to' the algebraic sum of said eflections.

5. Apparatus as in claim 3, including means for recordin on a chart the movement of said third e ement.

6. The combination of a north-seeking gyro-compass, an independently acting static gyroscopic azimuth-indicating instrument, two elements respectively operatively associated with said opic instruments and responsive to their azimuthal deflections, a third element, and means operatively asso ciated with both first mentioned elements and with said third element and adapted to impart to said third element a movement proportional to the algebraic sum of said deflections. and means controlled by said third element -for applying an azimuthal correction to said static instrument.

7. The combination of a =---:u-

gyro-compass, an independently acting static gyroscopic azimuth-indicating instrument, two elements respectively operatively associated with said gyroscopic instruments and responsive to their azimuthal deflections, a third element, and means operatively associated with both first mentioned elements and with said third element and adapted to impart to said third element a movement proportional to the algebraic sum of said deflections and means controlled by said third element for applying a couple about the horizontal axis on which the gyro casing of said static instrument is pivoted to cause a corrective precession in azimuth.

8. Apparatus as in claim 6, wherein said corrective means comprises two coils mounted on the vertical ring wherein the gyro casing of said static instrument is pivoted, means for supplying current to said coils, means for varying said current in accordance with the movement of said third element and a magnet rigidly associated with said gyro casing and in operative relation with said coils.

In testimony whereof I have signed my nameto this specification.

SIDNEY GEORGE BROWN. 

